Maternal behaviors and environmental factors can negatively impact fetal development. Alcohol is a leading cause of fetal abnormalities and fetal alcohol syndrome, which causes distinctive facial features and intellectual disabilities. Smoking during pregnancy doubles the risk of complications like placenta previa and placental abruption. Illicit drugs and certain medications also pose risks to the developing fetus. Untreated maternal diseases, stress, and nutritional deficiencies increase health risks as well. Proper prenatal care is important for monitoring risks and promoting healthy pregnancies.

1. Chapter 3 Part 2

3. Development and the Prenatal Environment
Teratogen – from teras for “monster” and genesis for
“origin,” any agent that can cause permanent damage to
the embryo or fetus
Dose-response effect: the relationship between the
dosage of a substance and the result of exposure
Threshold effect: related to the dose-response effect,
the point of exposure below which no effect can be
identified

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Environmental Influences on Prenatal Development
Sensitive Periods in
Prenatal Development

5. Alcohol
Alcohol is one of the most common causes of birth
abnormalities and one of the most preventable causes
of birth defects.
Fetal Alcohol Syndrome (FAS): characterized by
distinctive facial features, intellectual disabilities (IQ
less than 70), and physical growth below the 10th
percentile in height or weight for age and race.

6. Fetal Alcohol Syndrome
• FAS can cause many physical,
mental and behavioral
abnormalities
• Caused by maternal moderate to
heavy drinking during the
embryonic period
• Most harm is often done before the
mother even knows she is
pregnant.

7. Tobacco
Women who smoke during pregnancy are twice as likely to
experience two specific complications:
Placenta previa: a condition in which the placenta
attaches low on the wall of the uterus, with the potential to
cause bleeding late in pregnancy
Placenta abruptio: a life-threatening emergency
condition in which the placenta peels away from the wall
of the uterus, causing massive bleeding

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Environmental Influences on Prenatal Development
Nicotine inhibits
availability of oxygen to
the fetus
Smoking may alter the
embryo’s epigenetic
profile

10. Drugs and Medications
Cocaine - affects the brain, heart rate, and blood
pressure of both mother and fetus.
Increases the risk of miscarriage, premature birth, and death.
Opiates: - six times more likely to experience
complications during pregnancy. The fetus may
experience withdrawal symptoms, which causes fetal
distress.

11. OTC Medications
Medications: The FDA has a classification system
for drugs to guide physicians’ decisions regarding
medications.
Herbal medicines and supplements: Chemical
compounds created by nature are largely
unregulated. Women should discuss the use of
these substances with their professional health care
provider.

15. Maternal Disease, Illness, and Stress
Communicable diseases: may be caused by viruses, bacteria, or
parasites that cross the placenta or are transmitted during vaginal
birth.
Some diseases may cause serious birth defects depending on
timing and extent of exposure.
HIV and AIDS: attacks the immune system, leaving the person
vulnerable to infections and eventually leading to death.
AIDS can be transmitted during pregnancy, vaginal birth, and
breastfeeding.

19. Gestational Diabetes

20. High-Risk Pregnancies
Prenatal care: health care during pregnancy which monitors
health of mother and baby, provides education and counseling
about pregnancy, birth, and newborns to women and their
partners
Preeclampsia: a treatable medical condition that begins after the 20th
week, characterized by high blood pressure, protein in the urine, and
sometimes swelling
Eclampsia: a medical emergency which left untreated leads to maternal
seizures and/or coma and even death of mother and baby

22. Ectopic pregnancy: a condition in which the
blastocyst phase of the embryo implants
outside of the uterus, usually in the fallopian
tube, where it cannot continue to develop. It
quickly outgrows the space, resulting in pain
and possible rupture of the fallopian tube.
Rh incompatibility: a complication of
pregnancy in which a mother who is Rh
negative carries an Rh-positive fetus; under
certain conditions, antibodies in the mother’s
blood can attach the fetus’s red blood cells.

23. Nearly 1 million pregnant women in the United
States do not receive adequate prenatal care.
Lack of access to quality affordable health care
increases the risk of complications.
Prenatal Health Care